Thermal energy storage materials (TESMs) are known and have been used in applications for storing heat for subsequent use. Many TESMs are phase change materials, meaning they undergo a phase change, typically between solid state and liquid state, and can store (or release) a considerable amount of the heat, regarded as latent heat from the phase change. Much attention has been devoted toward devices that contain TESMs, and that use the TESMs to store and discharge thermal energy. Some of these devices have been called “heat batteries”. See, e.g., U.S. Pat. Nos. 7,225,860; 6,784,356; and 6,102,103 purport to depict examples of heat batteries. Heat batteries have been proposed for use in a number of applications. For example, U.S. Pat. No. 6,875,407 purports to use a vacuum insulated heat battery for improving catalytic efficiency. Other applications are identified, for example, in U.S. Pat. No. 6,102,103 (addressing engine warming, defrosting, or passenger compartment heating).
Despite efforts to develop such heat storage devices, it is observed that their structures may vary, dependent upon such factors as the desired operating temperatures to which the systems are exposed, the desired rate of heat exchange, the nature of the TESM employed or others. One particular respect in which heat storage devices vary is in the structures employed for containing the TESM. Another is in the manner in which individual containers that hold the TESM interface with any other such containers to afford a desired heat exchange response.
U.S. Pat. No. 7,225,860 purports to depict the use of encapsulation tubes to hold TESM. U.S. Pat. No. 6,102,103 purports to depict a jacket to contain TESM.
An example of an array of capsules carried on a common planar carrier has been offered by a company named Rubitherm GmbH, using a designation CSM Panel. It is believed that those structures, while potentially suitable for paraffin or hydrated salt TESMs, which tend to find utility at relatively low operating temperatures, may be not be suitable for applications subject to more rigorous conditions. In use, it appears that the CSM panels are stacked relative to each other in a housing to define modules through which a heat exchange fluid is passed.
Efforts to achieve good results from an encapsulation technique may further be complicated based upon the application under consideration. For example, some TESMs are very corrosive. Some TESMs will only function over a limited temperature range. Some encapsulation techniques are not sufficiently robust to withstand repeated thermal cycling.
Accordingly, particularly if a TESM system is to be employed efficiently in applications such as those previously attempted, there is a need for a robust TESM encapsulation system that withstands corrosion, provides a large amount of heat storage and transfer per unit volume, withstands relatively high operating temperatures (e.g., to about 300° C. or higher), or any combination thereof. It is also important that any such TESM encapsulation system be sufficiently versatile that it can be incorporated into a heating module in a manner that allows for good thermal efficiency. It is also important that any such TESM encapsulation system (and the systems in which it is introduced) can withstand considerable thermal cycling through the operational temperature range.